In Act 7.1.4, Armoured assualt node lane starting with OG Iron Man, I'm using 5* Medusa and placing armour shatter on opponent so that opponent do not trigger armour up buffs and go unblockable.
But opponent are still able to trigger armour up buffs(not consistently) after inflicted with armour shatter and description under Medusa armour shatter states : "Opponent cannot trigger armour up buffs when inflicted with armour shatter".
YouTube video link :
https://youtu.be/9NvmIRdbo7k